use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/golang.org/x/oauth2/jwt/jwt.go

@@ -9,7 +9,6 @@
 package jwt
 
 import (
-	"context"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -19,6 +18,7 @@ import (
 	"strings"
 	"time"
 
+	"golang.org/x/net/context"
 	"golang.org/x/oauth2"
 	"golang.org/x/oauth2/internal"
 	"golang.org/x/oauth2/jws"
@@ -61,11 +61,6 @@ type Config struct {
 
 	// Expires optionally specifies how long the token is valid for.
 	Expires time.Duration
-
-	// Audience optionally specifies the intended audience of the
-	// request.  If empty, the value of TokenURL is used as the
-	// intended audience.
-	Audience string
 }
 
 // TokenSource returns a JWT TokenSource using the configuration
@@ -110,9 +105,6 @@ func (js jwtSource) Token() (*oauth2.Token, error) {
 	if t := js.conf.Expires; t > 0 {
 		claimSet.Exp = time.Now().Add(t).Unix()
 	}
-	if aud := js.conf.Audience; aud != "" {
-		claimSet.Aud = aud
-	}
 	h := *defaultHeader
 	h.KeyID = js.conf.PrivateKeyID
 	payload, err := jws.Encode(&h, claimSet, pk)
@@ -132,10 +124,7 @@ func (js jwtSource) Token() (*oauth2.Token, error) {
 		return nil, fmt.Errorf("oauth2: cannot fetch token: %v", err)
 	}
 	if c := resp.StatusCode; c < 200 || c > 299 {
-		return nil, &oauth2.RetrieveError{
-			Response: resp,
-			Body:     body,
-		}
+		return nil, fmt.Errorf("oauth2: cannot fetch token: %v\nResponse: %s", resp.Status, body)
 	}
 	// tokenRes is the JSON response body.
 	var tokenRes struct {